Figure 1:
Schematic of foreshock geometry and spacecraft
locations in the V-B plane (the plane that contains the solar
wind velocity and the IMF) for 01-11 UT, May 11.

Figure 2:
Simultaneous observed magnetic field data in the foreshock
(red) and in the undisturbed solar wind (blue) on May 11. The top
panels are time series of the magnetic field. The bottom panels are
corresponding power spectra (the sum of power in all
three components).

Figure 3:
Dynamic power spectra of Polar magnetic field data in By
GSM component from 07 to 10 UT on May 11 (top) and May 14 (bottom).

Figure 4:
Dynamic power spectra of the H-component of ground-based
magnetic field from IGPP/LANL mid-latitudes stations AFA, LAL,
and SGD.